Gear mechanism



Oct. l13, 1959 swENsoN i 2,908,130 `GEAR MECHANISM Original Filed Sept.. 10. 1954` "Il Il nllllllllllllllli United States Patent GEAR MECHANSM Thure R. Swenson, Evanston, Ill., assignor to Raymond T. Moloney, Chicago, Ill.; American N alional'Bank and Trust Company of Chicago, executor of said Raymond T.`Moloney, deceased 4Substitute for abandoned application Serial No. 455,113, September 110, 1954. This application May 4, 1956, Serial No.1582,847 f 3 Claims. (Cl. 74-421) This disclosure providesan improved reduction gear system which is particularly suited for use in fractional horsepower motors, one of the principal features being the simplification of the housing gear box castings and elimination of studs, bosses, bearingseats, and like formations, heretofore necessary in such castings to seat the various gears involved, this application being substituted for application Serial No.` 455,113, filed September 10, 195'4,`now abandoned.

A further object is the provision of a more efficient, and at the same time less costly, gear unit by mounting a plurality of gears on one shaft with the elimination of expensive, space-consuming, and structure-weakening stud, boss, and other bearing formations or seats in the gear box, and the consequent possibility of employing heavier gears in the enlarged space thus made available.

Additional advantages attending the improved gear system and housing structure are a decrease in structural failures in both the gearing and housing, greater ease of Fig. 4 is another fragmentary sectional detail along lines 4--4 of Fig. 2.at the motor shaft.

The combination motor and reduction gear unit depicted in Fig. 1 includes a gear box or housing 10 in the form of a die-casting having bosses 11 for mounting of a sr'nall induction'motor 12, and a Ifront cover plate 13 removably secured by screws 14.

The motor 12 is of conventional design except that the front bearing 16 (Fig. 4, also) is not carried by the motor, as is the rear bearing 15, but instead consists of a casting 16A held on the housing by screws 17 with a nipple 16B fitting into a bore in the housing and an insert sleeve bearing 18 fitted into the bore of the nipple.

Thus, the input power shaft 19 of the motor is aligned for coaction with the gear` system.

, As seen in Pig. 2, there are only three shafts or gear axes involved in the simplified gear system, one being the power or input shaft 19, a second being the stub shaft 22 (Fig. 3 also), and the third and last being the output or load shaft 30.

As seen in Fig. 3, the output shaft 30 is mounted for rotation in an inner insert bearing 31 in the housing, and a larger sleeve bearing 32 pressed into a seat 13A formed as part of the cover plate. A thrust ball bearing 33 is provided at the inner end of shaft 30.

All but one of the reduction gears on the power output HSC Alatentc-ati 0st. 13, 1959 shaft 30` are floating free thereon, while all of the gears on the stub shaft float freely thereon, there being only a small driving pinion v20 (Fig. 2) fixed on the motor driveshaft 19 inposition to mesh with a fibre or like nonmetallicgear 34 fioating on shaft 30 (as in Figs. 2, 3, and 4)..

The driven fibre gear 34 has affixed toit a pinion 34A (Figs.` 3 and 4) meshing with driven gear 23 floating on the stub shaft 22, said gear 23 likewise having a pinion 23A secured to it and driving a gear 35 whichfloats on the power output shaft.`

The driven floating gear 35 has a pinion 35A affixed thereto and driving a floating gear 24 on the stub shaft, whichv gear likewise hasl a fixed pinion 24A vdriving a fixed and final gear 36- press-fitted onto shaft 30 to'turn the latter at the desired output speed determined by the ratiosof the train of intermediate oating gears 23 24A and 34 35A.

Heretofore gear reduction units for fractional horsepower motors have employed stub and pin shafts in necessary numbers and locations in the gear box with a resultantV crowding of the components, difiiculty in assembly or in gaining laccess to parts for servicing, and a costly necessity for fitting the stub shaft into seats or pressing home the pin shafts or bearings or providing for inserts in the mold for the box.

The present disclosures therefore afford a compact, less expensive, more' rugged and eiiicient reduction gear characterized by the provision of a stationary stub shaft anda rotatable work shaft with a train of intermeshing reduction gears fioating free on both shafts to drive a final fixed output gear on the power shaft in the last stage from power received from amotor pinion driving a fioating gear on the power shaft in the first or input stage.

The respective tandem sets of primary and secondary gears on these two shafts (eg. 34--35-36 on 30 and 23-24 on 22) turn in the same direction on their respective shafts and tend to equalize and reduce wear, which generally occurs on only one side of the shafting in the old-style gear-train system. If required, the stub shaft 22 can be made revolvable to carry this equalization even farther, although for most applications it is sufficient to have only the power shaft revolve.

Size for size, with respect to overall bulk, the new motor and more particularly its reduction gear system is considerably more powerful and rugged than the older types, and will consistently handle yloads ordinarily calling for larger and much more expensive motors of the old type, including some which employ worm gears.

I claim:

. l. In a motor and gear mechanism a housing having a backwall, a surrounding sidewall structure defining a cavity open on its side opposite said backwall, the latter having a bore therethrough into said cavity; a motor bearing removably mounted on the backwall for alignment with said bore, a motor having -a rotor shaft mount-y ed on said backwall with said shaft supported by said bearing to enter said cavity and having a drive pinion disposed in the cavity; said motor having a seco-nd motor bearing also supporting said rotor shaft cooperably with the first motor bearing; a cover plate for said cavity, a pair of parallel shafts in the cavity and seated at their respectively opposite end portions in means onsaid backwall and cover plate, one of said shafts constituting Van output shaft and having a final driven lgear fast thereon; gear means fioating free on 4both of said shafts and cooperatively forming a gear train, a first floating gear of which meshes with said drive pinion and a last gear of which meshes with said driven output gear, said drive pinion being eccentric relative to said parallel shafts,

guiso 2. In a gear mechanism, va housing, a motor carried bythe housing and having a drive shaft supported near one end by bearing means on the motor and near an opposite end by bearing means carried by said housing, said latter end entering the housing and having a driving pinion thereon; a power output shaft in the housing and having a iinral driven gear fast thereon and, also free gears floating thereornv an intermediate stubrshaft inthe housing and having free oating gears thereon intermeshing with the free gears on the power shaft to define afgear train iinally driving said final gear on the'power shaft, said motor driving pinion having driving intermesh with a iirst one of said free gearstof the train,` and turning on an axis eccentric ofthe-axes Vof the other two shafts.V

3. A combination motor and gear mechanism compris- -ing a motor having a statorvassembly and a rotor and rotor shaft; together with a cooperative change-ratio'gear mechanismrincluding a housing` comprising a she11 open 'ally of a major central axis between said lbottom'wall and cove'rrplate, providing a through-bearing supporting said rotor shaft at one side of the rotor for entry into said housing; means located of said bottom Wall supportably engaged by said stator assembly with said rotor 25 shaft aligned withV said throughbearing; means providing a second bearing for the rotor; shaft at the distal side of thestator assembly from said bottom wall and the through-bearing, said through-bearing and second bearing constituting the sole journal means for'therotor; a stub shaft and a load shaft Asupported with portions disposed interiorly of the housing by said bottom wall and cover and both Veccentric of saidnrnajor axis, said loadshafthaving an output gear lfixed thereon driven from a floating stub shaft gear and then projectingithrough the cover for coupling with a load; and agtrain ofcooperal tive change-ratio gears within the housing`A and .variouslyl distributed on said stub and load shafts, allfof the gears on the stu-b shaft floating thereon and some' of the `gears on the Iload shaft floating thereon including a-flo'ating input gear, said train being driven bypinion meanson the rotor shaft meshing` with saidfloating input gear. t

ReferencesvCited inthe tiheof'this4 patent j? Y UNITED STATES PATENTS o Thomson gm- Mar. -12,I 1895 Y535,643 ff642,765'

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent Non 2,908,180 October 13, 195" Thure R Swenson It is hereby certified that error appears in the printed specifica-bio:

of the above numbered patent requiring correction andl that the said Letter Patent should readas corrected below.

Column 3, linev 24, for "located of said read elocated on ,said we@ Signed and sealed this 10th day 'of May 1960.

(SEAL) Attest:

KARL H. vAXLINE ROBERT C. WATSON Attesting OfIcer Commissioner of Patents UNITED STATES PATENT OFFICE CERTIFICATE OE CORRECTION Patent No., 2,908,180 October 13, 1959 Thure R., Swenson It is hereby certified that error appears in the printed specification of the above numbered patent .requiring correction and that the said Letters Patent should read as corrected below.

Column 3, line 24, for "located of said" read -mlocated on said est,

Signed and sealed this 10th day of May 19601 (SEAL) Attest:

KARL II. .AXLINE ROBERT C. WATSON Attesting eer Commissioner of Patents 

